It is amazing to me even in today's age where you will see so many carved instruments with cracks that could have been prevented with the correct moisture in a room. A small humidifier ( air drawn, not steam !! ) in a room where your bass is stored ( if you have a plywood bass I would not worry about it ) set at least 50% to 65%, will keep her right where she needs to be, and it also creates good air quality for your dry nose in the winter... 